*{
  margin:0px;
  padding:0px;
}
ul,li{
  list-style: none;
}
img{
  display: block;
}
html,body{
  height: 100%;
}
.claerfix:after{
  content:"";
  display:block;
  clear:both;
}
#main{
  height: 100%;
  display: flex;
  flex-direction: column;
}
#content{
  flex: 1;
  overflow: auto;
  margin-bottom: 50px;
  position: relative;
  display: flex;
  flex-direction: column;
}